JSIO URLs

Posted on by

The clever bit about JSIO is the placeholder URLs – i.e. the “jsio.gif#…” that goes in your image src attributes and background-image CSS properties. Everything after the “#” is the filename of the image that should be displayed. It doesn’t have to be the filename at all, it could just be a single letter or number or symbol or whatever. It doesn’t matter to JSIO. To JSIO, everything after the “#” is just a key into the resources object that holds data uri encoded images. As long as the key is unique (which it will be if you use filenames, since no two files in the same directory can have the same name), JSIO is happy.

Using filenames as keys into our resources object is beneficial to humans. Much more beneficial than coordinates in a sprite, simply because (hopefully) the filenames are meaningful; they describe the image. In comparison to sprites, the JSIO resources object also makes maintaining your image data much easier as it is trivial to add or remove images without having to move other images around within the sprite (and consequently all coordinates referencing your moved image).

Another benefit of using filenames as keys into the JSIO resources object is for fallback. If JSIO detects your browser is IE7 or lower, it’ll strip out “jsio.gif#” leaving just your image key as the image src, which is hopefully a valid URL to the original image. Also, if JSIO detects you’re running IE8 and the image data is larger than 32KB it’ll do the same thing*.

* …but not yet in v1.0.0 alpha

Since the image key is after the “#” (it is the URL “fragment”), your browser won’t send multiple requests for the 1*1px jsio.gif file – it’ll just send one request, cache the response, and use it again. By the way, the jsio.gif image is just a transparent 1*1px gif (for maximum efficiency), but it could be an “spinner” image or something, which is shown temporarily whilst the JSIO resources file is downloaded.

—

This post is about JSIO – JSIO is a tiny library that allows you to make fewer requests to your server by packaging all your site image data in a JavaScript file in data uri format. The official site for JSIO can be found here: jsio.freestyle-developments.co.uk. You can read more about why I started this project here.

8,045 thoughts on “JSIO URLs”

  5. Woah! I’m really loving the template/theme of this website.
    It’s simple, yet effective. A lot of times it’s challenging to get that “perfect balance” between usability and visual appearance.
    I must say you’ve done a fantastic job with this. Also, the blog loads extremely fast for me on Safari.

    Superb Blog!

  10. Подборка шаблонов юридических документов для бизнеса и частных лиц: договоры, заявления, соглашения и иные формы. Переходите по запросу шаблоны юридических документов. Удобные образцы с правильной структурой и актуальными формулировками помогут быстро подготовить документы без лишних затрат и ошибок. Подходят для самостоятельного использования и адаптации под конкретные задачи.

  11. در جمع‌بندی کلی

    برای کسایی که دنبال

    پلتفرم‌های شرطی

    دنبالشن

    این پلتفرم شرطی

    کاملا میتونه

    گزینه مناسب محسوب بشه

    از سوی دیگر

    مجموعه‌هایی مثل

    enfejɑronline معتبر

    و

    sibƄet آنلاین

    حضور پررنگی دارن

    در نهایت

    قابل استفاده بود

    و

    در دفعات بعد

    مراجعه می‌کنم

    My web-site آموزش مهارت

  13. Minedrop — захватывающий слот в стиле Minecraft!
    Копайте блоки, собирайте ресурсы и выигрывайте крупные призы.
    Уникальная механика падающих символов создаёт цепочки побед где поиграть в майн дроп.
    Погрузитесь в пиксельный мир приключений и богатств!

  14. وقت بخیر، بنده مدتی قبل در حال جستجودر اینترنت به این
    سایت برخوردم وصادقانه برام
    جالب بود. محتواش جذاب بود و خیلی کم
    پیش میاد همچین منبعی ببینم.
    احساس می‌کنم برای کاربرای زیادی ارزش دیدن داره.
    اگه دنبال اطلاعات کامل هستن حتما سر بزنن.
    به طور کلی تجربه خوبی بود و قطعا باز هم
    سر می‌زنم

    به طور کلی

    برای علاقه‌مندان به

    شرط آنلاین

    فعال هستن

    این آدرس

    کاملا میتونه

    انتخاب مناسبی باشه

    همچنین

    برندهای شناخته‌شده‌ای مثل

    سایت еnfejaronline

    و

    سایت sibbet

    تونستن کاربرا جذب کنن

    جمع‌بندی کلی

    مناسب بود

    و

    در دفعات بعد

    دوباره سراغش میام

    .

    Hеrе is my blog – بورس ایران

  23. May I just say what a relief to find a person that genuinely understands what they are discussing online.
    You definitely realize how to bring an issue to light and make
    it important. A lot more people should look at this and understand this
    side of the story. I can’t believe you are not more popular because
    you surely have the gift.

  24. Excellent post. Keep writing such kind of information on your page. Im really impressed by your site. Hello there You have done an incredible job. I will certainly digg it and for my part recommend to my friends. I am sure theyll be benefited from this website. 在线购买他达拉非片用于肛交XXX色情

  32. Good afternoon Dominate the Dragonflight expansion with our dragonflight gold service designed for players. WoW gold guide included with every gold purchase. Learn to farm yourself. More detailed information on the website – https://www.wow-power-leveling.org/Gameplay/wow-raid-locations-map wow gold instant delivery safe power leveling wow leveling guide wow progression boost wow classic gold wow power leveling Good luck and good gameplay

  34. Hi, I do believe your blog could be having browser compatibility
    problems. When I look at your website in Safari, it looks fine however,
    if opening in I.E., it has some overlapping issues. I merely wanted
    to give you a quick heads up! Apart from that, excellent
    site!

  40. After checking out a few of the blog posts on your
    web site, I honestly like your technique of
    blogging. I bookmarked it to my bookmark website list
    and will be checking back in the near future. Please check out my website as well and let me know how you feel.

  41. Шаблоны юридических документов — удобное решение для быстрого и грамотного оформления договоров, заявлений и иных правовых бумаг. Переходите по запросу примеры и образцы правовых документов. Готовые формы разработаны с учетом законодательства и помогают избежать ошибок. Скачивайте, адаптируйте под свою ситуацию и экономьте время на подготовке документов без лишних затрат.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>